Friction drive for hoisting apparatus



Jan. i6, 1951 1 TORQK FRIGTIGN DRIVE FOR HOISTING APPARATUS 4 Sheets-Sheet l Filed Aug. 28, 1946 `Fan, 16, 1951 J, TOROK FRICTION DRIVE FOR HOISTING APPARATUS 4 Sheets-Sheet 2 Filed Aug. 28, 1946Y 50 W I TNESSES '52 I N VEN TOR:

Jzzzus Tam/c,

BY A TTORNE YS.

gan.. 16, 195 J, TOROK FRICTIN DRIVE FOR HOISTNG APPARATUS 4 Sheets-Sheet 5 iled Aug. 2S, 1946 W l 'I'NESSES ATTORNEYS.

Jan.. 15, 1951 1-@ROK 2,538,061

FRICTION DRIVE FOR HOISTING APPARATUS Filed Aug. 28, 1946 4 Sheets-Sheet 4 INVENTUR.-

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ATTORNEYS.

Patented Jan. 16, 1951 UNITED STAT ESu PATENT OFFICE FRICTION DRIVE FOR' `HOISTIN G APPARATU Juliusv Torok,` Allentown,` Pa.; Anna Torok execu trix of said` Julius Torok, deceased Claims'.

in which the raising and` lowering operations, as*

well as the opening and closingof the bucket, are eiTected by two separate lines. With' such ap'- paratus it is at times required that the lin'es be moved in unison and at the same speed' so that neither line acquiresy any slack, and at other times it is necessary to effect a differential movement between such lines to open or close the bucket.

To` accomplish theA required' movements it' has' been proposed to operate the lines controlling the' bucket' by two` separate drums, one' being a load drum and the other. beingi a holding' drum, each operated by aA separate motor; or" by the same".` motor throughA a complicated and' costly" difieren` tial mechanism with brakes applied toeac'h drum. Alternatively a single hoisting drurn and motor may be used in association with. a load line, and1 a second motor may be mountedonl the. bucket to open and close it; or differential drunr hoi'sts' may beA employed in which the" drum diameter varies, the latter system being usefulA for lifts of fixed distances only; or a single' mechanically operated load line may be applieda to the bucket for raising and lowering: the same'withits opening or closing accomplished' by hand operation'.

The principal object of" thepresent invention' is to provide a hoisting apparatus which' is' relaitively simple in design; economical to manufacture, and requires less maintenancean'dis otherwise free of the diiculties encountered with the, various systems which have heretofore been proposed as mentioned above- A further object of the invention is to render it practicable to utilize a combination` involving one motor and two separate drums frictionally connected to each other by provision of means for controlling the frictional connection between such drums which is mechanically dependableand4 may be relied upon to producela constant force of the desired `magnitude to` insure-proper operation. Additionally provision is made for regulating the degree of friction-` between such drums, whenever itmay become expedient` to do so.

Another object ofthe invention is to provide brake mechanism for the frictionally connected.

drums of such character that the load drum is automatically held' against rotationwhenthe motor for operating it is shut oi' and the holding drum is subject to a braking pressure applied according tothe will? of` the operator.

Other objects and advantages of the invention will become more'- apparent from the description of'a practical* embodiment thereof which is hereinafter set forth having reference to the accompanying'di'awings, whereof: i

Fig. l represents' a side elevation of hoisting apparatus of this invention as appliedv to a grab bucket which is moved from. one location to anotherbymeans of an overhead' trolley Fig. 2 is" an end'V elevation' of said hoisting appanfatus',` asview'e'd from thei left ofFig. l, showing details of the braking mechanism by which the't-loperator controls the holding drum of the hois;

Fig. 3` is an enlarged plan'view of the' hoisting apparatus and portions of the trolley upon which it is mounted;`

Fig'. 4" is a vertical cross* section of the same takeita'sindicated `b'y thearrows" IKT-IV of Fig. 3;

Fig. 5 is a further enlarged vertical cross section, similar to Fig. 4, showing the' spring retainer at? the end of the holding drum of the hoist and' various parts associated therewith;

Fig. 6 is a vertical cross section at the spring retainentaken asI indicated by the'arrows VI-VI` ofy Fig.- 51; and` Fig. 7 isf a fragmentary section of a portion of' the holding drum and spring retainer, taken asr indicated by the arrows' VII-VII of` Fig. 6.

Fig. 8 isi a perspective view' of one of the bushings" by whichthe holding" drum is freely mounted upon its central shaft.

As'showni in Fig. l the" hoisting apparatus of this invention is illustrated in connection with" a grab bucket B- of conventional design having a l fixed-upper' head` I and a movable lower head 2.

Irr a manner welll known to those skilled in the art the grab bucket is operated' by means of a holding line 3 which isattached to the nxed head l` and which serves to sustain the weight of the bucket while it is--open an'd'by a load line 5 which ing operations require a differential movement of the holding line and load line, and during raising orA lowering of'the bucket it is desirable that the two lines be caused to move in unison atthe same speedso that neither line can acquire any slack.

Asshownin detail in 3 the hoisting appartus includes an electric hoisting motor i3 which is reversible and drives a shaft II. A solenoid brake I2 is associated with shaft I l and is so controlled that whenever the motor I3 is shut off the brake is automatically operative to hold shaft I I against rotation, and whenever the motor i3 is caused to run the brake is released. Such a solenoid brake and the circuits for controlling it are well known, and hence the electrical details thereof are not illustrated herein, and these parts are shown conventionally in dotand-dash lines. drum 2| through a reducing gear train consisting of gears and pinions l, 8, 9, IQ. Gear 1 is bolted directly to the drum 2| on which the load line 5 is wound, and the load drum 2| is securely flxed to shaft It so that it is positively driven by motor I3 and incapable of axial movement relative to the shaft I6.

The holding line drum 22 is driven by the load drum 2| through a frictional connection consisting of an annular disk 6, see Fig. 4, of brake lining or similar material which is interposed between the end faces of the contiguous drums 2| and 22 and protected by the flange 2o of drum 2|. Formed integrally with the holding drum 22 is a cylindrical surface 25 engaged by a brake mechanism 26, see Figs. l and 2. Whereas, the load drum 2| is fixed on shaft i6 and positively driven thereby, the holding drum 22 is free to rotate upon shaft I3 and to facilitate this bushings I1 are provided.

The holding drum 22 is slightly larger in diameter than the load drum 2|. At one end it is provided with a telescopic cylindrical housing 3D,

shown most clearly in Figs. 4 and 5, which con' sists of a cylindrical guard llt, a collar 4! and the end portion of the holding drum 22, and which contains therein six spiral springs 3| which serve to force the holding drum 22 towards the load drum 2|. The spiral springs 3| have their axes disposed in a circle about shaft I6, as shown in Fig. 6, and are each accommodated in cylindrical r^cesses 32 formed longitudinally in a spring retainer 60 and in the end portion of the load drum 22 and confined to axial movement 'by rigid torque elements in the form of pins 33. Interspaced between the six springs 3| are two guide rods 35, shown most clearly in Fig. 7, which prevent the spring retainer 6U from rotating relative to the holding drum 22 while permitting relative axial movement between these elements. By means of a bushing |9 the spring retainer 5!) rotates freely upon the shaft l5. The holding drum 22, the housing 3G and spring retainer et are drilled and fitted with suitable lubricating'fittings 21 which connect with radial passages 28, 28a and 23o leading to the bushings I1, IS.

As shown in Fig. 8, each bushing I1 is provided with a number of holes 2li and is internally grooved at 25 permitting lubricant admitted through passages 23, 28a to` be distributed throughout the length of the bushing and to pass from the interior surfaces to the exterior surfaces and vice versa so that all portions of the bushing are lubricated and the holding drum 22 will turn freely with respect to the `shaft i5. It may be assumed that the bushing I9 of the spring retainer 6i), though somewhat differently shaped, is similarly lubricated.

The cylindrical guard d bolted to the collar 4I on shaft i6 bridges the space between the end portion of holding drum 22 and spring retainer 6E) and prevents the entry of dust or other foreign matter into this space. Between spring retainer 60 and collar 4| a thrust bearing I5 is provided.

Shaft |I drives the main load vby downward movement of brake rod 41 operating through crank arms 48 affixed to a shaft t9.v At its lower end brake rod 41 is adjustably connected to an arm 5t on a shaft 5I. An additional arm 52 on shaft 5I is provided with a brake pedal 53 at the bottom of the operators lcab 54. In an obvious manner the operator can at all times control the degree of pressure applied through mechanism 25 to the holding drum 22.

The hoisting apparatus herein illustrated is mounted on a trolley 55, outlined in dot-anddash lines in Fig. 3, having wheels 56 engaging rails 51 suitably supported on beams 58. By means of a trolley motor 59, the apparatus may be moved back and forth along the rails 51. The trolley 55 is of a conventional design and forms no part of the present invention.

Inasmuch as holding drum 22 has a slightly larger diameter than the load drum 2|, there is a tendency for the holding line 3 to be taken up faster than the load line 5 when the bucket B is being raised. However, because of the light pressure exerted between the holding drum 22 and the friction disk 6 a slight slipping occurs but this pressure is nevertheless suflicient to keep the slack out of the holding line 3. The degree of friction between the two drums 2| and 22 should be constant and carefully regulated. Regulation is accompanied by means of adjusting nut 43. The construction and arrangement of the springs 3|, within which are partially housed within the spring retainer 60 and partially housed Within the end of the holding drum 22, is such as to provide for the application of a constant force of the correct magnitude to insure tension on the holding line 3 when the motor I3 is running and no braking pressure is applied to holding drum 22.

The operation of the hoisting apparatus is as follows: Upon the assumption that the bucket B is loaded and that it is being raised by the hoisting apparatus in order to transfer the load to a point where it is to be discharged, the motor I3 will be running in a direction which will cause the holding line 3 and load line 5 to wind upon the drums to which they are attached. The increased diameter of holding drum 22 will tend to take up the holding line 3 at a faster rate than the load drum 2| takes up the load line 5 but on account of the relatively small amount of friction between the two drums slippage will result and no slack will occur in the holding line. When the bucket B has been raised to the desired height motor I3 is stopped. The solenoid brake l2 then automatically stops shaft I| and all movement of the load drum 2| ceases. The brake mechanism 26 is then applied by the operator through the medium of brake pedal 53. Both drums are then held against rotation. By means of trolley motor 59 the bucket B may then be moved to a position above the point of discharge. To open the bucket and discharge its contents motor I3 is operated in a reverse direction, and brake pressure is applied at the holding drum 22. Under these conditions slippage occurs at the frictional connection 6. The load line 5 is payed out but the holding line aisee-meri drumZZis caused to rotateby.` the weightof the bucket, the` friction. disk liA being. insufficient' to hold?. it; and; the .loadw drnmis held. stationary by theisolenoidlbrake, I2..` The. resulting diiferential movementoflines anda closesthe bucket.; By means of the trolley motor 59 the bucket B is then returned to its original location and lowered by reenergizing motor I3. The holding drum 122 being larger in diameter than the load drum 2l will tend to pay out holding line 3 faster than load line 5, and to prevent this the operator applies a slight pressure at foot pedal 53 suflicient to slow down holding drum 22 to the point where both lines are kept taut but insufficient to stop.

the movement of the holding drum. When the bucket has almost reached the loading point the operator increases the pressure of brake mechanism 26 causing the load line 5 to be payed out faster than the other line so that the bucket opens and drops onto the pile of material to be conveyed.

To load and raise the bucket the operator then releases brake mechanism 26 and reverses motor I3. The load drum winds up the load line 5 and the jaws 4 automatically close upon the material. Again the operator applies a slight braking pressure upon the holding drum so that the two lines pull in unison as the bucket is raised. The cycle is now ready to be repeated.

It will be apparent that the hoisting apparatus thus described requires only a single motor for its operation and is relatively simple to manufacture as compared with apparatus involving separately operated drums or complicated differential mechanism, and at the same time the apparatus of this invention can be readily controlled by simple movements on the part of the operator. The ease of operation is in large measure due to the fact that the braking of the load drum is eiected automatically and that the friction springs 3| are so arranged and incorporated within the structure as to produce the desired degree of friction between the drums, this friction being constant in its application because movement of the holding drum and spring retainer is limited in one direction by the load drum 2l, which is xed on the shaft I6, and in the other direction by the thrust bearing I5, and proper regulation 4of the pressure at the frictional connection between the drums may be effected by means of adjusting nut 43 and its lock nut 44.

While I have described one example of the invention by reference to a speciic embodiment thereof it will be apparent that various changes may be made in the apparatus herein described and illustrated without departing from the spirit of the invention as defined in the accompanying drawings.

Having thus described my invention, I claim:

l. In a hoisting apparatus, the combination with a power-driven shaft of two contiguous drums, one of said drums being fixed on said shaft and positively driven thereby and the other drum being free to rotate upon said shaft and having a frictional connection with said fixed drum, a thrust bearing on said shaft, a spring retainer connected to said free drum and engaging said thrust bearing, guide rods for connecting said spring retainer to said free drum whereby said retainer rotates with the free drum While 6 liavihgfcapacityffor relative axialfmovement with respect" thereto; a telescopic housing forfsaid retainer andl thrust bearing; and a1 series of coil springs disposed within said telescopic housing i and betweensaidret'a-iner and freei drum, said spr-ings havingr theirH axesA disposed in a, circle about saidshaft forrurging the ree drum towards the fixed' drum;`

2. In `a` hoistingY apparatus, the combination with a power-driven shaft of two contiguous drums, one-ofisaiddrums` being xed on said sha-ft `and positively driven thereby and the other drum" being' free to. rotate upon-` said shaft and having a frictional connection with said` fixeddrum; a` thrustfbearing on said shaft, a spring retainer jo-urnaled for free rotation on said shaft between said free drum and thrust bearing, said spring retainer having one end in engagement with said thrust bearing and the other` end guidedly connected to said free drum by rigid torque elements whereby the spring retainer is caused to rotate with said free drum while having capacity for relative axial movement with respect thereto, and spring means interposed between and carried by said spring retainer and said free drum for urging the latter towards the fixed drum.

3. In a hoisting apparatus, the combination with a power-driven shaft of two contiguous drums, one of said drums being fixed on said shaft and positively driven thereby and the other drum being free to rotate upon said shaft and having a frictional connection with said fixed drum, a thrust bearing on said shaft, a spring retainer journaled for free rotation on said shaft between said free drum and thrust bearing, Said spring retainer having one end in engagement with said thrust bearing and the other end guidedly connected to said free drum by rigid torque elements whereby the spring retainer is caused to rotate with said free drum while having capacity for relative axial movement with respect thereto, and means at the end of said shaft for adjusting the position of said thrust bearing on said shaft to regulate the pressure exerted by said spring means.

4. In a hoisting apparatus, the combination with a power-driven shaft of two contiguous drums, one of said drums being fixed on said shaft and positively driven thereby and the other drum being free to rotate upon said shaft and having a frictional connection with said fixed drum, a thrust bearing on said shaft an annular spring retainer `iournaled for free rotation on said shaft between said free drum and thrust bearing, said spring retainer having one end in engagement with said thrust bearing and the other end guidedly connected to said free drum by rigid torque elements whereby the spring retainer is caused to rotate with said free drum while having capacity for relative axial movement with respect thereto, a telescoping housing for said spring retainer and thrust bearing, and spring means interposed between and carried by said spring retainer and said free drum within said telescopic housing for urging the free drum towards the fixed drum.

5. In a hoisting apparatus the combination with a power-driven shaft of two contiguous drums, one of said drum being xed on said shaft and positively driven thereby and the other drum being free to rotate upon said shaft and having at one end a frictional connection with said iixed drum, and being longitudinally recessed at its other end, a thrust bearing on said shaft, a spring retainer journaled for free rotation on said shaft between said free drum and thrust bearing, said spring retainer having one end in engagement With said thrust bearing and having its other end longitudinally recessed and gudedly connected to said free drum whereby the spring retainer is caused to rotate with said free drum While having capacity for relative axial movement with respect thereto, and Spring means housed partially within the recesses of said spring retainer and partially within the recesses 0f said free drum for urging the free drum towards the xed drum.

JULIUS TOROK.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

